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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 35 |
| 5 | 123 |
| 6 | 495 |
| 7 | 1989 |
| 8 | 8309 |
| 9 | 35051 |
| 10 | 151437 |
| 11 | 659819 |
| 12 | 2913973 |
| 13 | 12976939 |
| 14 | 58299997 |
| 15 | 263670833 |
| 16 | 1200259447 |
| 17 | 5492958255 |
| 18 | 25263912743 |
| 19 | 116702563415 |
| 20 | 541237283707 |
| 21 | 2519080782283 |
| 22 | 11762908211343 |
| 23 | 55090441132491 |
| 24 | 258716199460163 |
| 25 | 1218036100384603 |
| 26 | 5747824726594467 |
| 27 | 27181821363396903 |
[1,1,3,9,35,123,495,1989,8309,35051,151437,659819, 2913973,12976939,58299997,263670833,1200259447, 5492958255,25263912743,116702563415,541237283707, 2519080782283,11762908211343,55090441132491, 258716199460163,1218036100384603,5747824726594467, 27181821363396903] |